The present invention relates to a component suction nozzle elevating device which selectively elevates or lowers a suction nozzle for sucking and holding a component and can change a top dead center position of the nozzle when the component is mounted or the like.
Conventionally, various structures of such a component suction nozzle-elevating device are known. For example, as shown in FIGS. 14 to 17, a ball screw shaft 202 is forwardly and reversely rotated by a rotary drive of a motor 201 so that an elevating plate 203 having a nut screw-threaded to the ball screw shaft 202 is raised or lowered. Flanges 208 are supportedly brought into contact with this elevating plate 203 at which four nozzle elevating shafts 211 penetrate through respective through holes 204. Each nozzle elevating shaft 211 has a nozzle 210 capable of sucking a component at a lower end thereof while provided with an elevation drive air cylinder 205 at an upper end thereof. Since each nozzle elevating shaft 211 is urged downward by a spring 206 in the elevation drive air cylinder 205 at all times, the flange 208 of each nozzle elevating shaft 211 is brought into contact with the elevating plate 203. When the elevating plate 203 is raised or lowered by the rotary drive of the motor 201, each nozzle elevating shaft 211 is guided by a guide unit 209 and raised or lowered.
FIG. 14 shows a state at the original point. When a nozzle is selected, as shown in FIG. 15, the elevating plate 203 is first lowered by a rotary drive of the motor 201 and the flange 208 of each nozzle elevating shaft 211 is separated from the elevating plate 203 by overcoming an urging force of the spring 206. Then, the elevation drive air cylinder 205 of a nozzle elevating shaft 211 having one selected nozzle 210 is driven to lower the nozzle elevating shaft 211 and the flange 208 is brought into contact with the elevating plate 203.
Subsequently, as shown in FIG. 16, while the elevating plate 203 is lowered by the rotary drive of the motor 201, the elevation drive air cylinder 205 of the selected nozzle elevating shaft 211 is driven to lower the nozzle elevating shaft 211. Then, a component is sucked by the nozzle 210 of the lowered nozzle elevating shaft 211 and mounted at a prescribed position on a board.
However, if vertical movement operation driven by the motor 201 and that of the air cylinder 205 are simultaneously started at the time of selecting one nozzle, the nozzle elevating shaft 211 does not immediately start lowering due to compressibility of air or the like even when air is supplied to the air cylinder 205 as compared with lowering operation of the elevating plate 203 by the motor 201. Therefore, as shown in FIG. 16, such a cylinder drive delay may occur that the flange 208 of the nozzle elevating shaft 211 may lower later than the elevating plate 203. Then, the flange 208 of the nozzle elevating shaft 211 catches up with the elevating plate 203 by a drive of the air cylinder 205 and brought into contact therewith. However, an impact due to this contact is transmitted to the nozzle elevating shaft 211 and a component sucked by the nozzle 210 at the lower end of the nozzle elevating shaft 211 can be displaced or dropped
Furthermore, as shown in FIG. 17, when all the nozzles are selected and top dead center positions of the nozzle elevating shafts 211 are adjusted by elevating all the nozzle elevating shafts 211, all the nozzle elevating shafts 211 need to be raised via the elevating plate 203 by a motor overcoming activating forces of all the air cylinders in order to raise all the nozzle elevating shafts 211. Therefore, the motor is overloaded.
Accordingly, an object of the present invention is to provide a component suction nozzle elevating device with which no impact is applied to a nozzle elevating shaft so that a component sucked by a nozzle is not displaced or dropped while a process time can be shortened by setting an optimal nozzle elevating stroke, by which the abovedescribed issues can be solved.
The present invention is constituted as described below to achieve the above object.
According to a first aspect of the present invention, there is provided a component suction nozzle elevating device comprising:
a plurality of nozzle elevating shafts supporting a suction nozzle for sucking and holding components at respective lower ends thereof with the nozzles normally urged upward;
a plurality of nozzle selecting actuators which are disposed corresponding to the plurality of nozzle elevating shafts and, when one suction nozzle to be lowered is selected from the plurality of nozzles, lowers a cylinder corresponding to the selected nozzle elevating shaft having the selected suction nozzle towards the nozzle elevating shaft in a range where the cylinder is not brought into contact with the selected nozzle elevating shaft;
a rotary drive device for elevation which simultaneously lowers all the nozzle selecting actuators to bring the cylinder selectively lowered by the nozzle selecting actuator into contact with the selected nozzle elevating shaft in order to lower the nozzle elevating shaft; and
a top dead center changing device which changes a position of a top dead center of each of the nozzle elevating shafts.
According to a second aspect of the present invention, there is provided a component suction nozzle elevating device according to the first aspect, further comprising an elevating member to which all the nozzle selecting actuators are fixed and which is screw-thread to a screw shaft connected to a rotating shaft of the rotary drive device for elevation and raised or lowered by forward and reverse rotation of the screw shaft, wherein the elevating member is raised or lowered by the forward- and reverse rotation of the screw shaft so that all the nozzle selecting actuators are simultaneously raised or lowered.
According to a third aspect of the present invention, there is provided a component suction nozzle elevating device according to the second aspect, wherein
the elevating member has a through hole or notch through which an upper end portion of the nozzle elevating shaft can penetrate; when one suction nozzle to be lowered is selected from the plurality of nozzles, the upper end portion of the nozzle elevating shaft is positioned in the through hole or notch in a range in which the upper end portion of the nozzle elevating shaft is not projected above the through hole or notch and a lower end of the cylinder of the nozzle selecting actuator is lowered until brought into contact with an edge of the through hole or notch; a gap is formed between the lower end of the cylinder and the upper end portion of the nozzle elevating shaft in the through hole or notch; and, when the elevating member is lowered by a rotary drive of the rotary drive device for elevation, the lower end of the cylinder and the upper end portion of the nozzle elevating shaft are brought into contact with each other so that the nozzle elevating shaft for elevating is lowered by the lower end of the cylinder.
According to a fourth aspect of the present invention, there is provided a component suction nozzle elevating device according to the second aspect, wherein a flat plate portion with which the lower end of the cylinder is brought into contact and which can be depressed is fixed to the upper end portion of the nozzle elevating shaft; when one suction nozzle to be lower is selected from the plurality of nozzles and the lower end of the cylinder is lowered, a gap is formed between the lower end of the cylinder and the flat plate portion of the upper end portion of the nozzle elevating shaft; and, when the elevating member is lowered by the rotary drive of the rotary drive device for elevation, the lower end of the cylinder and the flat plate portion of the upper end portion of the nozzle elevating shaft are brought into contact with each other and the nozzle elevating shaft is lowered by the lower end of the cylinder.
According to a fifth aspect of the present invention, there is provided a component suction nozzle elevating device according to any one of the first to fourth aspects, wherein the top dead center changing device is constituted by a top dead center changing cylinder having an engaging portion engaged to the nozzle elevating shaft on a piston rod; and the top dead center of the nozzle elevating shaft when the engaging portion of the piston rod is engaged to the nozzle elevating shaft by driving the top dead center changing cylinder is positioned below the top dead center of the nozzle elevating shaft when the engaging portion of the piston rod of the top dead center changing cylinder is unengaged to the nozzle elevating shaft.
According to a sixth aspect of the present invention, there is provided a component suction nozzle elevating device according to any one of the first to fourth aspects, wherein the top dead center changing device is constituted by a first top dead center changing actuator and a second top dead center changing actuator and has engaging portions engaged to the nozzle elevating shafts on the piston rods of the respective top dead center changing actuators; and a top dead center of the nozzle elevating shaft is positioned downward in an order of a top dead center of the nozzle elevating shaft when the engaging portion of the piston rod of the first top dead center changing actuator is unengaged to the nozzle elevating shaft, a top dead center of the nozzle elevating shaft when the engaging portion of the piston rod of the first top dead center changing actuator is engaged to the nozzle elevating shaft, and a top dead center of the nozzle elevating shaft when the engaging portion of the piston rod of the second top dead center changing actuator is engaged to the nozzle elevating shaft.
According to a seventh aspect of the present invention, there is provided a component suction nozzle elevating device according to any one of the first to fifth aspects, wherein
the nozzle selecting actuator is a nozzle selecting cylinder; the rotary drive device for elevation is an elevation drive motor; and the screw shaft is a ball screw shaft.
According to an eighth aspect of the present invention, there is provided a component mounting apparatus comprising:
component supply units for housing components sucked by the suction nozzles of the component suction nozzle elevating device;
a head drive device for moving a head having the component suction nozzle elevating device according to any one of the first to seventh aspects; and
a board conveying/holding device for holding a board on which components picked up by the suction nozzle of the component suction nozzle elevating device are mounted; the component mounting apparatus, wherein
the head is moved to the component supply unit by a drive of the head drive device and one selected suction nozzle is lowered so that a component is picked up by the component suction nozzle elevating device from the component supply unit; the head is moved from the component supply unit to the board by the drive of the head drive device; and the suction nozzle which is selected and picks up the component is lowered by the component suction nozzle elevating device to mount the component onto the board.